Appropriate research design, data management, and analysis are central to the success of the OAIC. The functions of the Design/Analysis and Data Management core are to provide consultations and services to investigators on all aspects of research design, implementation, analysis and reporting. Indeed, this core is referred to as the Design/Analysis and Data Management core to highlight the full spectrum of capabilities needed for the OAIC. The functions of this core will be accomplished by addressing the following specific aims: 1. Aid investigators in selecting and implementing an appropriate research design and to determine appropriate sampling, randomization and stratification procedures. 2. Aid investigators in the conduct of their studies by: (a) addressing issues of subject recruitment and retention, monitoring study progress and data collection procedures, and (b) developing, initiating and maintaining quality control measures for the conduct of the interventions, particularly related to protocol violations, endpoint monitoring, and ensuring subject safety. 3. Develop appropriate standardized methods for data collection and to ensure uniformity between and among studies, and when appropriate, to enhance collaborative and comparative analyses. 4. Develop or select data management systems and computer programs for data entry and editing and to maintain and document all databases. 5. Select or develop and implement appropriate analytic techniques for the evaluation of treatment effectiveness and cost-effectiveness. 6. Train and supervise junior faculty and junior investigators in the skills outlined in Aims 1-5.